This is unfortunate. However the Administration may try to ramp up funding. Which I agree with. However with the economy being what it is and budgetary cuts at all levels coming NASA may need to look to outside sources and partnerships for funding.

IXO and LISA are dead and disbanded as NASA missions.
We are looking at a very thin pipeline and few new missions for a while, unless there is drastic new direction from above and strong guidance on funding.

NASA is a mission oriented agency.
This is especially true of Astrophysics.

At any given time, there are operating missions, missions in development, and planned future missions, each at various stages of effort.
Each mission successfully launched has a nominal operating lifetime, after which it may be considered for an "extended mission", if possible.
NASA tends to have catastrophic successes, if the missions succeed at all, in that missions often operate way beyond their nominal lifetime, and if extended require continued Mission Operation and Data Analysis (MODA) funding.
This is cumulative, and gets expensive, even with marginal cost savings in later years.
On the other hand, shutting down a functioning mission seems kinda wasteful...

Operating missions are periodically reviews through the Senior Review process, most recently done in 2010.

Er, that's it.
Fermi and Kepler may be extended.
Hubble has a finite lifetime - depends on solar activity, more active the Sun, the hotter the upper atmosphere of the Earth and higher drag, the shorter the lifetime.
Sun is currently quiet, too quiet.
Hubble also has finite life expectancy for gyros, power and electronics.

TPF was pushed to the back of the line for various reasons and is currently very much a concept rather than a mission, but chasing very hot science

JWST is a budget disaster, way over budget and late.
JWST has been taken out of the Astrophysics division, with its notional budget, and stuck out there as a separate line item. It has a strictly pro forma budget in NASA's plans, and Congress needs to make a decision on whether to ramp up its funding, delay it or cut it completely.
It is hung out there as an awfully tempting ~ $2G chunk that would make a high profile target for would be target cutters.

W-FIRST is the notional priority, based on the decadal recommendation for rescoping the pre-existing JDEM (Joint Dark Energy Mission - joint with DoE) mission concept.
W-FIRST is a concept right now, not a spec'd mission.
JDEM had jumped previous mission priorities in a mid-decade review, last decade, but languished since.

IXO is a rebranding of the long wished for next large x-ray observatory. Previously Con-X.

LISA has been a mission concept for 14+ years. For much of that time, ESA has been under the impression that it is an approved mission with a target launch date, and a formal memorandum of understanding to that effect.
NASA, not so much.

Anyway: so now Astrophysics division has formally deleted LISA and IXO from the development queue.

That means science teams go home, development stops, done.

W-FIRST has no funding wedge - JWST and HST operations eat all the money.
So even though it is a priority, there is no devlopment ramp up and no launch date.
Everything now waits on JWST.

Europe, ESA, is taking its ball home and rethinking its own priority list for large missions.
They tend to take the "turtle" approach, and will continue on their way, and hopefully launch something.

NASA has to
a) wait to hear what budget they have and when
b) completely reprioritize everything in Astrophysics.
Possibly literally everything, if JWST gets deleted by Congress, which is a definite possibility.

So, whole careers are thrown out the window, there are people who spent 10-20 years on the mission development - there is also very little left in the NASA pipeline, there could be just 1-2 operating missions by 2015, and a gap of several years before anything flies, depending on the budget they get, failure of current missions and developing missions keeping to their timeline.
A lot of scientists are supported by the MODA funding of these missions, and a lot of that is looking to go away.

On the other hand, NASA will, hopefully, have some Astrophysics funding, and hopefully something will fly eventually, or be extendable and extended...

The Committee on Astrophysics and Astronomy (NRC) will be set up again, maybe with some fresh blood, and new concepts and priorities will be evaluated.
There are clearly opportunities in this crisis, as is often the case.

Short term, this will be very very painful.
Medium term, there is very high uncertainty with some opportunities.
Long term, hard to predict...</span>